Computers have now become an integral part of our society both in business and in residential settings. Almost every business of sufficient size in Germany, the United States, and other developed countries have one or more computers to assist them in running their businesses. Similarly, many families in those countries now have computers at home that are used to run various applications including games.
Some attribute the popularity of the computers to the Internet. The Internet provides people with a ready access to vast amounts of data. Many people now get their news, sports, stock, entertainment, and other information primarily from the Internet. Businesses have also embraced the Internet. The Internet provides the opportunity for computers to communicate instantly with other computers or individuals. Business processes that were once restricted to intranets and their users are now moving to the Internet. Accordingly, companies are moving more and more of their data to electronic forms. In addition, companies have amassed huge amounts of data in an effort to understand their business, improve performance, and build stronger employee, customer, and partner relationships.
Today, distributed computing systems are widely used by various organizations to accommodate the ever-increasing demand for the computer resources from consumers and businesses alike. In a distributed computing system, nodes (e.g., computers, processors, servers, etc.) are grouped or clustered to perform certain functions. Generally, a cluster is a collection of nodes that work together to perform a function, so that in many respects the cluster can be viewed as a single computer. The nodes of a cluster are usually coupled by a network, such as the Internet or an intranet. The cluster may be managed either statically (i.e., static cluster management) or dynamically (i.e., dynamic cluster management).
A static cluster is a group of application servers that participate in some form of workload management. With a static cluster, the application servers that are in a cluster are managed statically, and once defined, all the application servers in the cluster are usually started or stopped all at once. In short, the application servers are statically assigned to a specific cluster of nodes.
In contrast, dynamic clusters are controlled by autonomic controllers (or dynamic cluster managers) that optimize the performance of the cluster. In a dynamic cluster, individual instances of application servers can be started and stopped as required. A dynamic cluster manager may also dynamically manage the workloads of the nodes of the cluster based on performance information collected from cluster nodes. Consequently, dynamic clusters optimize the use of the processing capabilities of the nodes in the clusters. When compared to a single computer or even a statically managed cluster, the dynamically managed cluster may provide increased performance by better utilizing the existing processing capabilities of the cluster.
Virtualization is another mechanism for optimizing processing at a computer. Virtualization provides a software layer that when executed allows multiple virtual machines with, in some cases, different operating systems to run side-by-side with other virtual machines running on the same physical machine (e.g., a node, computer, processor, server, and the like). The virtualization software provides a so-called “container” that wraps and isolates the virtual machine from other virtual machines. For example, in a server complex including fifty physical servers, each of which hosts its own application server, virtualization permits the server complex to instead operate with, for, example, twenty-five physical servers, each of which includes virtualization software providing two virtual machines for the application servers. In both cases, fifty application servers are deployed, but with virtualization, the number of physical servers is reduced. Virtualization software may provide one or more of the following functions: running multiple virtual machines with different operating systems at the same time on the same physical machine; generating fully configured isolated virtual machines with a set of virtual hardware including an operating system and applications; saving, copying, and provisioning of virtual machines; and moving virtual machines from one physical machine to another physical machine for workload management.